Seeing red Research on conditions such as anaemia and malaria is set to get a boost following the identification of a clutch of new genes that influence red blood cells.

The discovery comes from an analysis of genetic samples from around 135,000 people, which was carried out by a large international team of researchers and is published today in the journal Nature.

"This helps us understand the biological mechanisms of what determines formation and function of red blood cells," says Australian co-author and geneticist, Dr Manuel Ferreira from the Queensland Institute of Medical Research in Brisbane.

Red blood cells are important because they contain haemoglobin, which carries oxygen.

Understanding the genes that impact the formation and function of red blood cells not only helps in basic understanding of biology, it will also help in research on diseases such as anaemia, says Ferreira.

Genome studies

To investigate the genetic factors influencing red blood cells, Ferreira and colleagues combined the results of a number of genome-wide association studies.

These studies looked at 2.6 million genetic variants to find out which ones show an association with 6 different red blood cell characteristics, including red blood cell count and haemoglobin concentration.

"There were 75 positions on the genome that were strongly associated with one or more of the red blood cell characteristics," says Ferreira, adding these explain up to 9 per cent of variance per trait.

He says of the genetic variants identified, 43 had not been previously identified.

Interestingly, says Ferreira, some of the implicated genes are known to be involved in a number of rare blood diseases.

He says this shows variation in the same gene can lead to either slight differences in red blood cell count or haemoglobin concentration, or much more drastic conditions.

Fellow co-author Professor Peter Visscher of the University of Queensland says the team also carried out an RNA-silencing experiment in drosophila and compared the results with those from published mouse studies.

These animal models confirmed the influence of a number of the genes on red blood cells.

"It's interesting because it shows those genes were already important so many hundreds of millions of years ago when a common ancestor of drosophila and humans lived," says Visscher.

Clinical significance

Professor Douglas Hilton, director of the Walter and Eliza Hall Institute in Melbourne describes the research as a "tour de force".

He says while it's hard to say how far off it will be before it has an effect on human health, the research will be key in focusing future studies in understanding blood and its disorders.

"We're intrinsically interested in finding out which of the 25,000 genes in your genome are responsible for red blood cells," says Hilton.

"For us this is really exciting because it's going to change the way we look at our research problems," he adds. "It identifies 75 new leads that we can work on."

Hilton says slight differences in red blood cells can contribute to how someone responds to parasites such as malaria, which attack red blood cells.

"Some people become extremely anaemic rather than mounting additional production of red blood cells in response to infection," he says.